Antigen/antibody specificity exchanger

ABSTRACT

An antigen/antibody specificity exchanger is disclosed. It comprises: A) an amino-acid sequence corresponding to an amino-acid sequence of an antibody which specifically binds to a certain antigen, including hapten, B) linked by a link to C) an amino-acid sequence to which a certain antibody binds. Also, a diagnostic reagent comprising an antigen/antibody specificity exchanger according to the invention is disclosed. Said reagent may be e.g. used instead of antisera or monoclonal antibodies in in vitro testing systems, such as immunological tests. Further, a method of treating a disease or disorder caused by a known antigen in an individual in need of an increased number of antigen-specific antibodies is disclosed. In the method a tailor-made antigen/antibody specificity exchanger of the invention is issued. Said method may be e.g. used to redirect a patient&#39;s antibodies against poliovirus to fight HIV infection in said patient.

The present invention relates to an antigen/antibody specificity exchanger, which comprises an amino-acid sequence which specifically binds to a certain antigen linked to an amino-acid sequence to which a certain antibody binds. In vitro the antigen/antibody specificity exchanger of the invention can be used as a diagnostic reagent instead of antisera or monoclonal antibodies in testing systems, and in vivo it can be used to redirect antigens or antibodies to other antibodies or antigens, respectively, than they were originally directed to.

BACKGROUND

During the past decade the antigenic structure of several viral proteins have been characterized using synthetic peptides, such as the human immunodeficiency virus-1(HIV-1)gp160, and the hepatitis B virus core/e antigens (HBc/eAg). Recently it has been shown that a synthetic peptide corresponding to the complementarity determining region 3 of the heavy chain (CDRH3) of a monoclonal antibody (mAb; F58), directed to the variable third (V3) domain of HIV-1 gp160, may act as a mini antibody and neutralize HIV-1 in vitro. In the experimental part of the present specification, the construction of synthetic peptides combining the CDRH3 domain of the mAb F58, or CDRH1, CDRH2, CDRH3 domain of Ab C1-5, and antigenic regions derived from the HIV-1 gp41, HBc/e antigen, hepatitis C virus (HCV) core protein or from the poliovirus VP1, is shown. These peptides specifically bound the V3 domain of HIV-1. Thus, it was possible to modify the antigenic surface of HIV-1 V3 peptides. This antigen/antibody specificity exchanger will be used for redirecting the reactivity of circulating antibodies and using already existing antibody specificities for a predetermined purpose. It may also serve to alter the composition of the surface of proteins by the addition of foreign determinants. For example, the widely used poliovirus vaccination, together with the high rate of seropositivity to enteroviral proteins may be a suitable pool of antibodies to redirect against other pathogens, such as HIV.

The complementary determining regions (CDRs) of antibodies are responsible for the specificity of the antibody (1,2). X-ray crystallography has shown that the three CDRs of the variable (V) region of the heavy chain and the three CDRs of the V region of the light chain may all have contact with the epitope in an antigen-antibody complex (3). Single peptides corresponding to the CDRs of mAbs to various antigens have been shown to mimic the recognition capabilities of the respective mAb (4-10). Recently it was shown that a peptide corresponding to CDRH3 of a mAb specific for the V3 region of human immuno deficiency virus-1, holds neutralizing capacity when assayed in vitro (9). It was also observed that the CDRH2 of a mAb to hepatitis B core antigen (HBcAg) is capable of capturing HBcAg (10).

DESCRIPTION OF THE INVENTION

The present invention is, in one aspect, directed to an antigen/antibody specificity exchanger, which comprises

A) an amino-acid sequence corresponding to an amino-acid sequence of an antibody which specifically binds to a certain antigen, including hapten,

B) linked by a link to

C) an amino-acid sequence to which a certain antibody binds.

The amino-acid sequence of A) may comprise additional amino acids or sequences on one or both sides of the amino-acid sequence of an antibody which specifically binds to a certain antigen, including hapten. Such additional amino acids and sequences may be, but are not limited to, the amino acids and sequences naturally occurring in said antibody as extensions to the amino-acid sequence of A). The number of amino-acid residues in the amino-acid sequence of A) is preferably at least 5, and is together with possible extensions preferably less than 35.

Further, the amino-acid sequence of C) may comprise additional amino acids or sequences on one or both sides of the amino-acid sequence to which a certain antibody binds. Such additional amino acids and sequences may be, but are not limited to, the amino acids and sequences naturally occurring as extensions to the amino-acid sequence of C). The number of amino-acid residues in the amino-acid sequence of C) is preferably at least 5, and is together with possible extensions preferably less than 35.

In an embodiment of the above aspect of the invention said antigen/antibody specificity exchanger of the invention is one wherein said amino-acid sequence of A) corresponds to an amino-acid sequence of a complementarity determining region (CDR) or a framework region of a certain antibody.

In a further embodiment said antigen/antibody specificity exchanger of the invention is one wherein said amino-acid sequence of C) corresponds to an antibody-binding region of a certain protein, such as one of viral, bacterial or fungal origin.

In another embodiment said antigen/antibody specificity exchanger of the invention is one wherein said amino-acid sequence of A) is linked to said amino-acid sequence of C) by a link B), which is selected from the group consisting of a direct peptide bond and spacer molecules, such as an amino acid, an amino acid having two amino groups, linear or branched peptides or polypeptides and biotin-avidin-biotin.

In a preferred embodiment said antigen/antibody specificity exchanger of the invention is one wherein said amino-acid sequence of A) is selected from the group consisting of

SEQ ID NO: 1: Cys Asp Leu Ile Tyr Tyr Asp Tyr Glu Glu Asp Tyr Tyr Phe

SEQ ID NO: 2: Cys Asp Leu Ile Tyr Tyr Asp Tyr Glu Glu Asp Tyr Tyr

SEQ ID NO: 3 Thr Tyr Ala Met Asn

SEQ ID NO: 4 Arg Val Arg Ser Lys Ser Phe Asn Tyr Ala Thr Tyr Tyr Ala Asp Ser Val Lys Gly and

SEQ ID NO: 5 Pro Ala Gln Gly Ile Tyr Phe Asp Tyr Gly Gly Phe Ala Tyr

In another preferred embodiment said antigen/antibody specificity exchanger of the invention is one wherein said amino-acid sequence of C) is selected from the group consisting of

SEQ ID NO: 6: Pro Pro Asn Ala Pro Ile Leu Ser

SEQ ID NO: 7: Arg Pro Pro Asn Ala Pro Ile Leu Ser Thr

SEQ ID NO: 8: Lys Glu Ile Pro Ala Leu Thr Ala Val Glu Thr Gly

SEQ ID NO: 9: Pro Ala His Ser Lys Glu Ile Pro Ala Leu Thr Ala

SEQ ID NO: 10: Trp Gly Cys Ser Gly Lys Leu Ile Cys Thr

SEQ ID NO: 11: Cys Thr Thr Ala Val Pro Trp Asn Ala Ser and

SEQ ID NO: 12: Gln Arg Lys Thr Lys Arg Asn Thr Asn Arg Arg.

Specific examples of antigen/antibody specificity exchangers of the invention:

Peptide 1: SEQ ID NO: 13 Cys Asp Leu Ile Tyr Tyr Asp Tyr Glu Glu Asp Tyr Tyr Phe Pro Pro Asn Ala Pro Ile Leu Ser

Peptide 2: SEQ ID NO: 14 Cys Asp Leu Ile Tyr Tyr Asp Tyr Glu Glu Asp Tyr Tyr Phe Arg Pro Pro Asn Ala Pro Ile Leu Ser Thr

Peptide 3: SEQ ID NO: 15 Cys Asp Leu Ile Tyr Tyr Asp Tyr Glu Glu Asp Tyr Tyr Phe Lys Glu Ile Pro Ala Leu Thr Ala Val Glu Thr Gly

Peptide 4: SEQ ID NO: 16 Cys Asp Leu Ile Tyr Tyr Asp Tyr Glu Glu Asp Tyr Tyr Phe Pro Ala His Ser Lys Glu Ile Pro Ala Leu Thr Ala

Peptide 5: SEQ ID NO: 17 Cys Asp Leu Ile Tyr Tyr Asp Tyr Glu Glu Asp Tyr Tyr Phe Trp Gly Cys Ser Gly Lys Leu Ile Cys Thr

Peptide 6: SEQ ID NO: 18 Cys Asp Leu Ile Tyr Tyr Asp Tyr Glu Glu Asp Tyr Tyr Phe Cys Thr Thr Ala Val Pro Trp Asn Ala Ser ##STR1## Peptide 8: SEQ ID NO: 20 Thr Tyr Ala Met Asn Pro Pro Asn Ala Pro Ile Leu Ser

Peptide 9: SEQ ID NO: 21 Arg Val Arg Ser Lys Ser Phe Asn Tyr Ala Thr Tyr Tyr Ala Asp Ser Val Lys Gly Pro Pro Asn Ala Pro Ile Leu Ser

Peptide 10: SEQ ID NO: 22 Pro Ala Gln Gly Ile Tyr Phe Asp Tyr Gly Gly Phe Ala Tyr Pro Pro Asn Ala Pro Ile Leu Ser

Peptide 11: SEQ ID NO: 23 Cys Asp Leu Ile Tyr Tyr Asp Tyr Glu Glu Asp Tyr Tyr Gln Arg Lys Thr Lys Arg Asn Thr Asn Arg Arg

Another aspect of the invention is directed to a diagnostic reagent comprising an antigen/antibody specificity exchanger according to the invention.

Such a diagnostic reagent of the invention may be used to detect in vitro specific antigens in biological samples, e.g. body fluid or tissue samples. Thus, the diagnostic reagent of the invention may be used instead of antisera or monoclonal antibodies in in vitro testing systems, such as immunological tests, e.g. Enzyme-Linked Immunosorbent Assay (ELISA), Enzyme Immunoassay (EIA), Western Blot, Radioimmunoassay (RIA) etc. Further, the diagnostic reagent of the invention may be used to investigate biological properties of biological systems.

Still another aspect of the invention is directed to a method of treating a disease or disorder caused by a known antigen in an individual in need of an increased number of antigen-specific antibodies, which comprises administration to said individual of a sufficient amount of a tailor-made antigen/antibody specificity exchanger according to the invention which binds to certain antibodies known to exist in said individual.

An individual in need of an increased number of antigen-specific antibodies against a known antigen, which causes a disease or disorder in said individual, may be one who will benefit from getting a rapid increase in the number of such antigen-specific antibodies, or who even lacks or has insufficient ability to elicit antibodies against said known antigen. Said individual may be a human or non-human mammal.

Such a tailor-made antigen/antibody specificity exhanger according to the invention is designed so that certain antibodies existing in the patient in question, (e.g. antibodies against viral proteins, such as antibodies against poliovirus, antibodies against virus causing measles, antibodies against hepatitis B virus, antibodies against hepatitis C virus, antibodies against HIV-1, whether induced by natural infection or vaccination) binds to the amino-acid sequence of C) and the amino-acid sequence of A) binds to a known antigen causing a disease or disorder in said patient (e.g. HIV).

Thus, existing antibodies in said patent are redirected to said known antigen (against which said patient e.g. lacks or has insufficient amount of desired antibodies).

A specific example of an antigen/antibody specificity exchanger of the invention is a peptide which binds to antibodies against poliovirus and also binds specifically to HIV virus. Thus, already high titres in a patient of antibodies against poliovirus may thus be used to fight HIV infection in said patient.

Preparation of the Antigen/Antibody Specificity Exchanger of the Invention

The antigen/antibody specificity exchanger of the invention is prepared in any suitable manner known in the art. It is in most cases a peptide, with the exception of the case when it comprises biotin-avidin-biotin as a linker. As is well-know in the art, peptides can be produced by genetic engineering methods or peptide synthesis. In peptide synthesis one amino-acid residue is coupled to the next one in liquid phase, or starting with the solid phase to which the C-terminal of the first amino acid is coupled, whereupon the C-terminal of the next amino acid is coupled to the N-terminal of the first amino acid, etc, finally releasing the build-up peptide from the solid phase.

The antigen/antibody specificity exchangers presented in Table 1 are all synthetic peptides synthesized according to a method for multiple peptide synthesis (21) and by a Milligen 9050 peptide synthesizer using 9-fluorenylmethoxy-carbonyl-protected amino acid esters (20). All peptides were analysed and/or purified by reverse phase HPLC using a Pep-S 5 m column (Pharmacia-LKB, Uppsala, Sweden), run with a gradient from 10% to 60% CH3CN against water containing 0.1% trifluoro-acetic acid.

Testing of the Antigen/Antibody Specificity Exchanger of the Invention

Monoclonal Antibodies and Human Sera.

The production and characterization of mAb to HBc/eAg has been described (15, 18). The mAb 14E11 recognizes the epitope at residues 135-141 (PNAPILS), of the HBc/eAg sequence (15). The monoclonal antibody 14E11 was kindly provided by Dr. Alexander Cimanis, Riga. Two human sera (A and B) reactive to a peptide covering residues 42-55 of VP1 of poliovirus 1 have previously been described (19). A monoclonal antibody against enteroviral VP1 was purchased from Dako (CBV; M7064, Dako, Copenhagen, Denmark)

Three human sera (C, D and E) positive for antibodies to hepatitis C virus (HCV) core residues 7-19 have previously been described (20).

Enzyme Immuno Assays (EIAs).

Strain-specific HIV-1 V3 peptides were coated on microtiter wells (Nunc 96F Certificated; Nunc, Copenhagen, Denmark) in 100 ml portions at concentrations of from 10 mg/ml to 0.01 mg/ml in 0.05M sodium carbonate buffer, pH 9.6, at +4° C. overnight. Excess peptides were removed by washing with PBS containing 0.05% Tween 20.

The peptide-coated plates were assayed for binding using the peptides of the invention diluted from 100 mg/ml to 0.01 mg/ml in PBS containing 1% BSA, 2% goat serum, and 0.05% Tween 20. The dilutions of the peptides of the invention were added in 100 ml portions and incubated with the adsorbed V3 peptides for 60 minutes at +37° C. Excess test peptides were removed by washing and bound peptide was indicated by the respective mAb or anti-serum, by incubation for 60 minutes at +37° C. The amount of bound antibody was indicated by an additional incubation of enzyme-labelled secondary antibody, rabbit anti-mouse Ig (P260, Dako, Copenhagen, Denmark) for mAbs, and goat anti-human IgG (A-3150; Sigma Chemicals, St. Louis, Mo.) for human antibodies. The amount of bound conjugate was determined by addition of substrate and the absorbances were measured at 492 nm or 405 nm in a spectrophoto-meter.

Antibody Recognition of Peptides of the Invention.

When adsorbed to microplates all peptides of the invention presented in Table 1 except for Nos. 4 (Table 2) and 7 (data not shown) were found to be reactive with the respective antibodies.

Antigen Binding of the Peptides of the Invention.

The anti-genically functional test peptides were further evaluated for binding of HIV-1 V3 peptide, MN-strain. All test peptides which had a functional antigenic region were found to directly bind to the HIV-1 V3 peptide (Tables 3 and 4). As shown in Tables 3 and 4, the reactivity to the HIV-1 V3 peptide was found to be dependent on both concentrations of the test peptides and of V3 peptides, indicating a specific reactivity. This clearly indicates that it was possible to redirect antibodies specific for HIV-1 gp41, HBc/eAg and poliovirus 1 VP1 to bind to the altered antigenic surface of the HIV-1 V3 peptide. It was also found, that pre-incubation of equimolar concentrations of mAb 14E11 and the corresponding test peptide of the invention, did not change the ability of the test peptide mAb complex to bind to the V3 peptide (data not shown). This indicates that it is possible to add antigenic domains to a CDR peptide with retained antigen binding ability of the CDR sequence.

The ability of the antigen/antibody specificity exchangers to redirect antibodies was further evaluated in a system where the CDRH1, CDRH2 and CDRH3 sequences from mAb C1-5 were added to the epitope sequence for mAb 14E11. A peptide corresponding to the epitope sequence for mAb C1-5, residues 71-90 of HBc/eAg with an Ile at position 80, was adsorbed to microplates. The antigen/antibody specificity exchangers, based on the C1-5 CDRs, were then added, and the amount bound CDR peptide was indicated by the epitope specific mAb 14E11. The results clearly showed that the mAb 14E11 which originally recognized residues 134-141 of the HBc/eAg sequence was redirected by the antigen/antibody specificity exhanger containing the CDRH2 sequence (Table 5). Also, this reactivity was dependent on the amount CDR added, indicating a specific reaction (p<0.01, Regression analysis; Table 5).

Further, in Table 7 is shown that the antigen/antibody specificity exchanger of the invention can redirect an existing HBc/eAg specific antibody to significantly bind to HIV-1 V3 peptides of several different subtypes.

Thus, it is evident that the antigen/antibody exchanger of the invention forms the basis of a novel method for redirecting the specificity of monoclonal and polyclonal antibodies by modifying the antigenic surface of a viral protein.

It should be understood that the invention comprises antigen/antibody exchangers wherein included amino-acid sequences are chemically stabilized e.g. by cyclization and wherein included amino-acid sequences may have specific amino-acid deletions, additions and/or substitutions. Such modified amino-acid sequences may result in antigen/antibody exchangers exhibiting increased (or decreased) biological activities.

                  TABLE 1     ______________________________________     Antigen/antibody specificity exchangers of the     invention represented by peptides containing the CDRH3 domain of     mAb F58 or CDRH1, CDRH2, CDRH3 domain of mAb C1-5 (A) and     different antigenic regions derived from viral proteins (C).     Peptide           Amino-acid         Amino-acid                                       Source of     No.   sequence (A)                      link (B)                              sequence (C)                                       aas (C) Ref.     ______________________________________     1.    SEQ ID NO 1.                      peptide SEQ ID NO 6                                       HBc/eAg,                                               15                      bond             aas 134-141     2.    SEQ ID NO 1.                      peptide SEQ ID NO 7                                       HBc/eAg,                                               15                      bond             aas 133-142     3.    SEQ ID NO 1.                      peptide SEQ ID NO 8                                       Polio VP1,                                               16                      bond             aas 39-50     4.    SEQ ID NO 1.                      peptide SEQ ID NO 9                                       Polio VP1,                                               16                      bond             aas 35-46     5.    SEQ ID NO 1.                      peptide SEQ ID NO 10                                       HIV-1 gp41,                                               20                      bond             aas 596-605     6.    SEQ ID NO 1.                      peptide SEQ ID NO 11                                       HIV-1 gp41                                               20                      bond             aas 603-612     7.    2(SEQ ID   Lys     SEQ ID NO 7                                       HBc/eAg,                                               15           NO 1)                       aas 133-142     8.    SEQ ID NO 3.                      peptide SEQ ID NO 6                                       HBc/eAg,                                               15                      bond             aas 134-141     9.    SEQ ID NO 4.                      peptide SEQ ID NO 6                                       HBc/eAg,                                               15                      bond             aas 134-141     10.   SEQ ID NO 5.                      peptide SEQ ID NO 6                                       HBc/eAg,                                               15                      bond             aas 134-141     11.   SEQ ID NO 2.                      peptide SEQ ID NO 12                                       HCV core                                               22                      bond             8-18     ______________________________________      Note:      aas = amino acids

                  TABLE 2     ______________________________________     Testing of antigen/antibody specificity exchanger     of the invention represented by peptides passively     adsorbed to polystyrene for ability to be     recognized by antibodies specific for the antigenic     region presented in the peptide. Values are given as     the absorbance obtained at 492 or 405 nm.     Peptide            Antibody Amount peptides added (ng/0.1 ml) to solid phase     No.    used     1.000  100   10   1     0.1  0.01     ______________________________________     1      14Ell    2.500  1.675 0.030                                       0.010 0.009                                                  0.008     2      14E11    2.500  1.790 0.008                                       0.006 0.008                                                  0.006     3      CBV      2.500  1.142 0.036                                       0.020 0.019                                                  0.036            human A  1.945  1.850 0.486                                       0.088 0.115                                                  0.116            human B  1.342  0.770 0.130                                       0.065 0.090                                                  0.095     4      CBV      0.020  0.018 0.015                                       0.016 0.017                                                  0.018            human A  0.059  0.081 0.108                                       0.109 0.097                                                  0.100            human B  0.052  0.072 0.091                                       0.098 0.083                                                  0.100     ______________________________________      Note:      Regression analysis of the relation between absorbance and peptide      concentration gives p < 0.01.

                  TABLE 3     ______________________________________     Testing of the HIV-1 V3 peptide-antigen binding     capability of the CDR sequence simultaneously with     the ability to be recognized by monoclonal antibodies     specific for the antigenic region on the test peptide of     the invention. Values are given as the absorbance at 492     ______________________________________     nm.     a:     Pep- Anti-   Amount of Amount V3 peptide added     tide body    test peptide                            (ng/0.1 ml) to solid phase     No.  used    (ng/0.1 ml)                            1.000                                 500  250  125  62.5 31.25     ______________________________________     1    14E11   10,000    2.500                                 2.500                                      2.500                                           2.338                                                1.702                                                     1.198                  5,000     2.500                                 2.500                                      2.500                                           2.190                                                1.622                                                     1.122                  2,500     2.500                                 2.500                                      2.500                                           2.039                                                1.394                                                     0.990                  1,250     2.500                                 2.500                                      2.500                                           1.712                                                0.930                                                     0.771                  625       1.936                                 0.824                                      0.380                                           0.152                                                0.056                                                     0.053                  312       0.196                                 0.085                                      0.044                                           0.043                                                0.030                                                     0.025     b:     Pep- Anti-   Amount of Amount V3 peptide added     tide body    test peptide                            (ng/0.1 ml)     No.  used    (ng/0.1 ml)                            1.000                                 500  250  125  62.5 31.25     ______________________________________     4    14E11   10.000    2.500                                 2.500                                      2.133                                           1.560                                                1.070                                                     0.829                  5.000     2.500                                 2.500                                      1.963                                           1.645                                                1.074                                                     0.981                  2.500     2.500                                 2.500                                      1.729                                           1.404                                                0.962                                                     0.747                  1.250     2.500                                 2.424                                      1.433                                           1.327                                                0.795                                                     0.488                  625       0.835                                 0.359                                      0.200                                           0.120                                                0.088                                                     0.073                  312       0.099                                 0.054                                      0.042                                           0.049                                                0.045                                                     0.025     ______________________________________     c:     Pep- Anti-   Amount of Amount peptide added     tide body    test peptide                            (ng/0.1 ml) to solid phase     No.  used    (ng/0.1 ml)                            1.000                                 100  10   1    0.1  0.01     ______________________________________     3    CBV     10,000    0.523                                 0.498                                      0.162                                           0.161                                                0.017                                                     0.017                  1,000     0.053                                 0.054                                      0.031                                           0.027                                                0.010                                                     0.010                  100       0.034                                 0.037                                      0.025                                           0.029                                                0.010                                                     0.010                  10        0.023                                 0.022                                      0.014                                           0.014                                                0.010                                                     0.009                  1         0.013                                 0.044                                      0.014                                           0.017                                                0.027                                                     0.009                  0.1       0.011                                 0.009                                      0.008                                           0.032                                                0.013                                                     0.013     ______________________________________      Note:      Regression analysis of the relation between absorbance and CDR peptide      concentration, and relation between absorbance and V3 peptide      concentration gives p < 0.01, respectively.

                  TABLE 4     ______________________________________     Testing of the HIV-1 V3 peptide antigen binding     capability of the CDR sequence simultaneously with the     ability to be recognized by human anti-polio VP1     polyclonal antibodies specific for the antigenic     region on the test peptides of the invention. Values     are given as the absorbance at 405 nm.     Pep- Anti-   Amount of Amount V3 peptide added     tide body    test peptide                            (ng/0.1 ml) to solid phase     No.  used    (ng/0.1 ml)                            1.000                                 500  250  125  62.5 31.25     ______________________________________     a:     3    human   10,000    1.538                                 1.356                                      1.448                                           1.052                                                0.280                                                     0.123          A       5,000     1.179                                 1.050                                      1.006                                           0.557                                                0.136                                                     0.087                  2,500     0.684                                 0.558                                      0.604                                           0.216                                                0.084                                                     0.067                  1,250     0.367                                 0.358                                      0.332                                           0.162                                                0.075                                                     0.062                  625       0.228                                 0.238                                      0.220                                           0.121                                                0.083                                                     0.063                  312       0.171                                 0.154                                      0.154                                           0.103                                                0.072                                                     0.060     b:     3    human   10,000    0.366                                 0.352                                      0.352                                           0.200                                                0.074                                                     0.056          B       5,000     0.206                                 0.217                                      0.188                                           0.131                                                0.063                                                     0.053                  2,500     0.134                                 0.132                                      0.126                                           0.091                                                0.061                                                     0.055                  1,250     0.107                                 0.114                                      0.108                                           0.077                                                0.060                                                     0.054                  625       0.082                                 0.104                                      0.087                                           0.075                                                0.063                                                     0.056                  312       0.083                                 0.091                                      0.094                                           0.077                                                0.068                                                     0.060     ______________________________________      Note:      Regression analysis of the relation between absorbance and CDR peptide      concentration, and relation between absorbance and V3 peptide      concentration gives p < 0.01, respectively.

                  TABLE 5     ______________________________________     Testing of the HIV-1 V3 peptide antigen capability     of the CDR sequence simultaneous with the ability to     be recognized by human anti-HCV core polyclonal anti-     bodies specific for the antigenic region on the test     peptides of the invention. Values are given as the     absorbance at 405 nm.                    Amount                    of V3           Anti-    pepitide                            Amount of test peptide added     Peptide           body     (ng/0.1 (ng/0.1 ml)     No.   used     ml)     62   31   15   7.5  3.7  1.8     ______________________________________     11    human    625     2.500                                 2.416                                      2.097                                           1.473                                                0.973                                                     0.630           HCV-C    78      2.500                                 2.335                                      1.781                                           1.225                                                0.825                                                     0.564                    39      2.389                                 2.287                                      1.626                                           1.081                                                0.664                                                     0.389     11    human    625     1.999                                 1.490                                      1.184                                           0.751                                                0.458                                                     0.428           HCV-D    78      1.758                                 1.370                                      1.025                                           0.612                                                0.468                                                     0.380                    39      1.643                                 0.993                                      0.833                                           0.497                                                0.343                                                     0.287     11    human    625     2.368                                 2.165                                      1.656                                           1.104                                                0.645                                                     0.462           HCV-E    78      2.156                                 1.824                                      1.396                                           0.733                                                0.514                                                     0.352                    39      1.893                                 1.683                                      1.110                                           0.756                                                0.310                                                     0.272     ______________________________________

                                      TABLE 6     __________________________________________________________________________     Testing of C1-5 CDRs (10 ug/ml) (in test peptides of     the invention) with a peptide corresponding to     HBc/eAg corresponding to residues 71-90) coated on     solid phase. Bound CDR was indicated by the epitope     specific mAb 14E11.                 Amount c71-90            Antibody                 peptide                        Amount of test peptide added (ng/0.1 ml)     CDR sequence            used (ng/0.1 ml)                        10.000                            5.000                               2.500                                   1.250                                      625 312     __________________________________________________________________________     Peptide 8:            14E11                 625    0.003                            0.002                               0.002                                   0.002                                      0.002                                          0.002     CDRH1       312    0.002                            0.002                               0.004                                   0.003                                      0.006                                          0.004     (SEQ ID NO 3)            78   0.003  0.003                            0.005                               0.005                                   0.003                                      0.003     Peptide 9:            14E11                 625    2.500                            1.303                               0.070                                   0.012                                      0.003                                          0.002     CDRH2       312    2.500                            1.070                               0.058                                   0.011                                      0.003                                          0.002     (SEQ ID NO 4)                 78     2.500                            0.868                               0.039                                   0.008                                      0.003                                          0.003     Peptide 10:            14E11                 625    0.004                            0.003                               0.004                                   0.003                                      0.003                                          0.003     CDRH3       312    0.004                            0.003                               0.004                                   0.004                                      0.003                                          0.003     (SEQ ID NO 5)            78   0.005  0.004                            0.005                               0.005                                   0.004                                      0.004     __________________________________________________________________________

                  TABLE 7     ______________________________________     Redirecting existing HBc/eAg specific antibody (14E11,     from Dr. A. Tsimanis, Riga) to different subtype-     specific HIV-1 V3 peptides (subtypes A-E) via     specificity exchanger peptide containing CDRH3 sequence     against HIV-1 and a HBc/eAg epitope for mAb 14E11.     HIV-1 V3     peptide     attached Reactivity (absorbance at 405 nm) of specificity     to solid-              exchanger peptide added in the indicated amount (ng)     phase   500     250     125   62.5  31.25 15.625     ______________________________________     Subtype A             0.378   0.126   0.078 0.068 0.062 0.017     Subtype B             2.686   2.536   1.710 1.329 0.360 0.157     Subtype C             1.261   0.514   0.111 0.077 0.051 0.020     Subtype D             0.17    0.079   0.065 0.028 0.029 0.026     Subtype E             0.22    0.090   0.093 0.032 0.063 0.030     ______________________________________

REFERENCES

1. Kabat, E. A., Wu, T. T. & Bilofsky, H. (1976) Proc Natl Acad Sci USA 73, 4471.

2. Kieber, E. T. & Kohler, H. (1986) Immunol Rev 90, 29.

3. Amit, A. G., Maruzzia, R. A., Phillips, S. E. V. & Poljak, R. J. (1986) Science 233, 747.

4. Williams, W. V., Guy, R., Rubin, D. H., Robey, F., Myers, J. N., Kieber, E. T., Weiner, D. B. & Greene, M. I. (1988) Proc Natl Acad Sci USA 85, 6488.

5. Williams, W. V., Moss, D. A., Kieber, E. T., Choen, J. A., Myers, J. N., Weiner, D. B. & Green, M. L. (1989) Proc. Natl. Acad. Sci. USA 87, 5537.

6. Taub, R., Gould, R. J., Garsky, V. M., Ciccarone, T. M., Hoxie, J., Friedman, P. A. & Shattil, S. J. (1989) J. Biol. Chem. 264, 259.

7. Cohen, J. A., Williams, W. W., Weiner, D. B., Geller, H. M. & Greene, M. I. (1990) Proc. Natl. Acad. Sci. USA 87, 492.

8. Williams, V. W., Kieber, E. T., VonFeldt, J., Greene, M. I. & Weiner, D. B. (1991) J. Biol. Chem. 266, 5182.

9. Levi, M., Sallberg, M., Ruden, U., Herlyn, D., Maruyarna, H., Wigzell, H., Marks, J. & Wahren, B. (1993) Proc Natl Acad Sci USA 90, 4374.

10. Sallberg. M., Levi, M., Ruden, U., Pushko, P., Bichko, V., Magnius, L. O., Tsimanis, A. & Wahren, B. in Peptides: Chemistry and Biology (eds. Hodges, R. & Rivier, J.) In press (ESCOM, Leiden, 1993).

11. Machida, A., Ohnuma, H., Takai, E., Tsuda, F., Tanaka, T., Naito, M., Munekata, E., Miyakawa, Y./Mayurni, m. (1989) Mol. Immunol. 26, 431.

12. Salfeld, J., Pfaff, E., Noah, M. & Schaller, H. (1989) J. Virol. 63, 798.

13. Sallberg, M., Ruden, U., Magnius, L. O., Harthus, H. P., Noah, M. & Wahren, B. (1991) J. Med. Virol. 33, 248.

15. Sallberg, M., Pushko, P., Berzinsh, I., Bishko, V., Sillekens, P., Noah, M., Pumpens, P., Gren, E., Wahren, B. & Magnius, L. O. (1993) J. Gen. Virol. 74, 1335.

16. Roivanen, M., Narvanen, A., Korkolainen, M., Huhtala, M-L & Hovi, T. (1991) Virol 180, 99-107.

18. Bichko, V. V., Schodel, F., Nassal, M., Grene, E., Berzinsh, I., Borisova, G., Miska, S., Peterson, D. L, Gren, E. & Will, H. (1993) Mol. Immunol. 30, 221.

19. Cello, J., Samuelsson, A., Stålhandske, P., Svennerholm, B., Jeansson, S. & Forsgren, M. (1993) J. Clin. Microbiol. 31, 911-916.

20. Z X Zhang, M Chen, K Wallhagen, J Trojnar, L O Magnius, B Wahren, & M Sallberg. Molecular basis for antibody cross-reactivity between the hepatitis C virus core protein and the host-derived GOR protein. Clin. Exp. Immunol. 1994; in press.

21. Hougthen, R. A. (1985) Proc. Natl. Acad. Sci. USA 82, 5131.

    __________________________________________________________________________     SEQUENCE LISTING     (1) GENERAL INFORMATION:     (iii) NUMBER OF SEQUENCES: 23     (2) INFORMATION FOR SEQ ID NO:1:     (i) SEQUENCE CHARACTERISTICS:     (A) LENGTH: 14 amino acids     (B) TYPE: amino acid     (C) STRANDEDNESS: single     (D) TOPOLOGY: linear     (ii) MOLECULE TYPE: peptide     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:1:     CysAspLeuIleTyrTyrAspTyrGluGluAspTyrTyrPhe     1510     (2) INFORMATION FOR SEQ ID NO:2:     (i) SEQUENCE CHARACTERISTICS:     (A) LENGTH: 13 amino acids     (B) TYPE: amino acid     (C) STRANDEDNESS: single     (D) TOPOLOGY: linear     (ii) MOLECULE TYPE: peptide     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:2:     CysAspLeuIleTyrTyrAspTyrGluGluAspTyrTyr     1510     (2) INFORMATION FOR SEQ ID NO:3:     (i) SEQUENCE CHARACTERISTICS:     (A) LENGTH: 5 amino acids     (B) TYPE: amino acid     (C) STRANDEDNESS: single     (D) TOPOLOGY: linear     (ii) MOLECULE TYPE: peptide     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:3:     ThrTyrAlaMetAsn     15     (2) INFORMATION FOR SEQ ID NO:4:     (i) SEQUENCE CHARACTERISTICS:     (A) LENGTH: 19 amino acids     (B) TYPE: amino acid     (C) STRANDEDNESS: single     (D) TOPOLOGY: linear     (ii) MOLECULE TYPE: peptide     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:4:     ArgValArgSerLysSerPheAsnTyrAlaThrTyrTyrAlaAspSer     151015     ValLysGly     (2) INFORMATION FOR SEQ ID NO:5:     (i) SEQUENCE CHARACTERISTICS:     (A) LENGTH: 14 amino acids     (B) TYPE: amino acid     (C) STRANDEDNESS: single     (D) TOPOLOGY: linear     (ii) MOLECULE TYPE: peptide     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:5:     ProAlaGlnGlyIleTyrPheAspTyrGlyGlyPheAlaTyr     1510     (2) INFORMATION FOR SEQ ID NO:6:     (i) SEQUENCE CHARACTERISTICS:     (A) LENGTH: 8 amino acids     (B) TYPE: amino acid     (C) STRANDEDNESS: single     (D) TOPOLOGY: linear     (ii) MOLECULE TYPE: peptide     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:6:     ProProAsnAlaProIleLeuSer     15     (2) INFORMATION FOR SEQ ID NO:7:     (i) SEQUENCE CHARACTERISTICS:     (A) LENGTH: 10 amino acids     (B) TYPE: amino acid     (C) STRANDEDNESS: single     (D) TOPOLOGY: linear     (ii) MOLECULE TYPE: peptide     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:7:     ArgProProAsnAlaProIleLeuSerThr     1510     (2) INFORMATION FOR SEQ ID NO:8:     (i) SEQUENCE CHARACTERISTICS:     (A) LENGTH: 12 amino acids     (B) TYPE: amino acid     (C) STRANDEDNESS: single     (D) TOPOLOGY: linear     (ii) MOLECULE TYPE: peptide     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:8:     LysGlyIleProAlaLeuThrAlaValGlyThrGly     1510     (2) INFORMATION FOR SEQ ID NO:9:     (i) SEQUENCE CHARACTERISTICS:     (A) LENGTH: 12 amino acids     (B) TYPE: amino acid     (C) STRANDEDNESS: single     (D) TOPOLOGY: linear     (ii) MOLECULE TYPE: peptide     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:9:     ProAlaHisSerLysGlyIleProAlaLeuThrAla     1510     (2) INFORMATION FOR SEQ ID NO:10:     (i) SEQUENCE CHARACTERISTICS:     (A) LENGTH: 10 amino acids     (B) TYPE: amino acid     (C) STRANDEDNESS: single     (D) TOPOLOGY: linear     (ii) MOLECULE TYPE: peptide     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:10:     TrpGlyCysSerGlyLysLeuIleCysThr     1510     (2) INFORMATION FOR SEQ ID NO:11:     (i) SEQUENCE CHARACTERISTICS:     (A) LENGTH: 10 amino acids     (B) TYPE: amino acid     (C) STRANDEDNESS: single     (D) TOPOLOGY: linear     (ii) MOLECULE TYPE: peptide     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:11:     CysThrThrAlaValProTrpAsnAlaSer     1510     (2) INFORMATION FOR SEQ ID NO:12:     (i) SEQUENCE CHARACTERISTICS:     (A) LENGTH: 11 amino acids     (B) TYPE: amino acid     (C) STRANDEDNESS: single     (D) TOPOLOGY: linear     (ii) MOLECULE TYPE: peptide     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:12:     GlnArgLysThrLysArgAsnThrAsnArgArg     1510     (2) INFORMATION FOR SEQ ID NO:13:     (i) SEQUENCE CHARACTERISTICS:     (A) LENGTH: 22 amino acids     (B) TYPE: amino acid     (C) STRANDEDNESS: single     (D) TOPOLOGY: linear     (ii) MOLECULE TYPE: peptide     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:13:     CysAspLeuIleTyrTyrAspTyrGluGluAspTyrTyrPheProPro     151015     AsnAlaProIleLeuSer     20     (2) INFORMATION FOR SEQ ID NO:14:     (i) SEQUENCE CHARACTERISTICS:     (A) LENGTH: 24 amino acids     (B) TYPE: amino acid     (C) STRANDEDNESS: single     (D) TOPOLOGY: linear     (ii) MOLECULE TYPE: peptide     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:14:     CysAspLeuIleTyrTyrAspTyrGluGluAspTyrTyrPheArgPro     151015     ProAsnAlaProIleLeuSerThr     20     (2) INFORMATION FOR SEQ ID NO:15:     (i) SEQUENCE CHARACTERISTICS:     (A) LENGTH: 26 amino acids     (B) TYPE: amino acid     (C) STRANDEDNESS: single     (D) TOPOLOGY: linear     (ii) MOLECULE TYPE: peptide     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:15:     CysAspLeuIleTyrTyrAspTyrGluGluAspTyrTyrPheLysGlu     151015     IleProAlaLeuThrAlaValGluThrGly     2025     (2) INFORMATION FOR SEQ ID NO:16:     (i) SEQUENCE CHARACTERISTICS:     (A) LENGTH: 26 amino acids     (B) TYPE: amino acid     (C) STRANDEDNESS: single     (D) TOPOLOGY: linear     (ii) MOLECULE TYPE: peptide     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:16:     CysAspLeuIleTyrTyrAspTyrGluGluAspTyrTyrPheProAla     151015     HisSerLysGluIleProAlaLeuThrAla     2025     (2) INFORMATION FOR SEQ ID NO:17:     (i) SEQUENCE CHARACTERISTICS:     (A) LENGTH: 24 amino acids     (B) TYPE: amino acid     (C) STRANDEDNESS: single     (D) TOPOLOGY: linear     (ii) MOLECULE TYPE: peptide     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:17:     CysAspLeuIleTyrTyrAspTyrGluGluAspTyrTyrPheTrpGly     151015     CysSerGlyLysLeuIleCysThr     20     (2) INFORMATION FOR SEQ ID NO:18:     (i) SEQUENCE CHARACTERISTICS:     (A) LENGTH: 24 amino acids     (B) TYPE: amino acid     (C) STRANDEDNESS: single     (D) TOPOLOGY: linear     (ii) MOLECULE TYPE: peptide     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:18:     CysAspLeuIleTyrTyrAspTyrGluGluAspTyrTyrPheCysThr     151015     ThrAlaValProTrpAsnAlaSer     20     (2) INFORMATION FOR SEQ ID NO:19:     (i) SEQUENCE CHARACTERISTICS:     (A) LENGTH: 25 amino acids     (B) TYPE: amino acid     (C) STRANDEDNESS: single     (D) TOPOLOGY: linear     (ii) MOLECULE TYPE: peptide     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:19:     CysAspLeuIleTyrTyrAspTyrGluGluAspTyrTyrPheLysArg     151015     ProProAsnAlaProIleLeuSerThr     2025     (2) INFORMATION FOR SEQ ID NO:20:     (i) SEQUENCE CHARACTERISTICS:     (A) LENGTH: 13 amino acids     (B) TYPE: amino acid     (C) STRANDEDNESS: single     (D) TOPOLOGY: linear     (ii) MOLECULE TYPE: peptide     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:20:     ThrTyrAlaMetAsnProProAsnAlaProIleLeuSer     1510     (2) INFORMATION FOR SEQ ID NO:21:     (i) SEQUENCE CHARACTERISTICS:     (A) LENGTH: 27 amino acids     (B) TYPE: amino acid     (C) STRANDEDNESS: single     (D) TOPOLOGY: linear     (ii) MOLECULE TYPE: peptide     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:21:     ArgValArgSerLysSerPheAsnTyrAlaThrTyrTyrAlaAspSer     151015     ValLysGlyProProAsnAlaProIleLeuSer     2025     (2) INFORMATION FOR SEQ ID NO:22:     (i) SEQUENCE CHARACTERISTICS:     (A) LENGTH: 22 amino acids     (B) TYPE: amino acid     (C) STRANDEDNESS: single     (D) TOPOLOGY: linear     (ii) MOLECULE TYPE: peptide     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:22:     ProAlaGlnGlyIleTyrPheAspTyrGlyGlyPheAlaTyrProPro     151015     AsnAlaProIleLeuSer     20     (2) INFORMATION FOR SEQ ID NO:23:     (i) SEQUENCE CHARACTERISTICS:     (A) LENGTH: 24 amino acids     (B) TYPE: amino acid     (C) STRANDEDNESS: single     (D) TOPOLOGY: linear     (ii) MOLECULE TYPE: peptide     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:23:     CysAspLeuIleTyrTyrAspTyrGluGluAspTyrTyrGlnArgLys     151015     ThrLysArgAsnThrAsnArgArg     20     __________________________________________________________________________ 

I claim:
 1. An antigen/antibody specificity exchanger which ccmprises a first amino acid sequence having an amino acid sequence of a first antibody which specifically binds to an antigen, including a hapten, covalently linked to a second amino acid sequence to which a second antibody binds.
 2. An antigen/antibody specificity exchanger of claim 1, wherein said first amino acid sequence has an amino acid sequence of a complementarity determining region (CDR) of said first antibody.
 3. An antigen/antibody specificity exchanger of claim 1, wherein said second amino acid sequence has an antibody-binding region of a protein.
 4. An antigen/antibody specificity exchanger of claim 1, wherein said linkage is selected from the group consisting of a direct peptide bond and a spacer molecule.
 5. An antigen/antibody specificity exchanger of claim 2, wherein said first amino acid sequence is selected from the group consisting ofSEQ ID NO: 1 Cys Asp Leu Ile Tyr Tyr Asp Tyr Glu Glu Asp Tyr Tyr Phe SEQ ID NO: 2 Cys Asp Leu Ile Tyr Tyr Asp Tyr Glu Glu Asp Tyr Tyr SEQ ID NO: 3 Thr Tyr Ala Met Asn SEQ ID NO: 4 Arg Val Arg Ser Lys Ser Phe Asn Tyr Ala Thr Tyr Tyr Ala Asp Ser Val Lys Gly and SEQ ID NO: 5 Arg Val Arg Ser Lys Ser Phe Asn Tyr Ala Thr Tyr Tyr Ala Asp Ser Val Lys Gly.
 6. An antigen/antibody specificity exchanger of claim 3, wherein said protein is of viral, bacterial, or fungal origin.
 7. An antigen/antibody specificity exchanger of claim 6, wherein said second amino acid sequence is selected from the group consisting ofSEQ ID NO: 6 Pro Pro Asn Ala Pro Ile Leu Ser SEQ ID NO: 7 Arg Pro Pro Asn Ala Pro Ile Leu Ser Thr SEQ ID NO: 8 Lys Glu Ile Pro Ala Leu Thr Ala Val Glu Thr Gly SEQ ID NO: 9 Pro Ala His Ser Lys Glu Ile Pro Ala Leu Thr Ala SEQ ID NO: 10 Trp Gly Cys Ser Gly Lys Leu Ile Cys Thr SEQ ID NO: 11 Cys Thr Thr Ala Val Pro Trp Asn Ala Ser and SEQ ID NO: 12 Gln Arg Lys Thr Lys Arg Asn Thr Asn Arg Arg.
 8. An antigen/antibody specificity exchanger of claim 1, having a sequence selected from the group consisting ofSEQ ID NO: 13 Cys Asp Leu Ile Tyr Tyr Asp Tyr Glu Glu Asp Tyr Tyr Phe Pro Pro Asn Ala Pro Ile Leu Ser SEQ ID NO: 14 Cys Asp Leu Ile Tyr Tyr Asp Tyr Glu Glu Asp Tyr Tyr Phe Arg Pro Pro Asn Ala Pro Ile Leu Ser Thr SEQ ID NO: 15 Cys Asp Leu Ile Tyr Tyr Asp Tyr Glu Glu Asp Tyr Tyr Phe Lys Glu Ile Pro Ala Leu Thr Ala Val Glu Thr Gly SEQ ID NO: 16 Cys Asp Leu Ile Tyr Tyr Asp Tyr Glu Glu Asp Tyr Tyr Phe Pro Ala His Ser Lys Glu Ile Pro Ala Leu Thr Ala SEQ ID NO: 17 Cys Asp Leu Ile Tyr Tyr Asp Tyr Glu Glu Asp Tyr Tyr Phe Trp Gly Cys Ser Gly Lys Leu Ile Cys Thr SEQ ID NO: 18 Cys Asp Leu Ile Tyr Tyr Asp Tyr Glu Glu Asp Tyr Tyr Phe Cys Thr Thr Ala Val Pro Trp Asn Ala Ser ##STR2## SEQ ID NO: 20 Thr Tyr Ala Met Asn Pro Pro Asn Ala Pro Ile Leu Ser SEQ ID NO: 21 Arg Val Arg Ser Lys Ser Phe Asn Tyr Ala Thr Tyr Tyr Ala Asp Ser Val Lys Gly Pro Pro Asn Ala Pro Ile Leu Ser SEQ ID NO: 22 Pro Ala Gln Gly Ile Tyr Phe Asp Tyr Gly Gly Phe Ala Tyr Pro Pro Asn Ala Pro Ile Leu Ser and SEQ ID NO: 23 Cys Asp Leu Ile Tyr Tyr Asp Tyr Glu Glu Asp Tyr Tyr Gln Arg Lys Thr Lys Arg Asn Thr Asn Arg Arg.
 9. An antigen/antibody specificity exchanger which comprises an amino acid sequence having an amino acid sequence of a first antibody which specifically binds to an antigen, including a hapten, linked to an amino acid sequence to which a second antibody binds, wherein said linkage is achieved using biotin-avidin-biotin.
 10. A diagnostic reagent which comprises an amino acid sequence having an amino acid sequence of a first antibody which specifically binds to an antigen, including a hapten, covalently linked to an amino acid sequence to which a second antibody binds.
 11. A diagnostic reagent which comprises an amino acid sequence having an amino acid sequence of a first antibody which specifically binds to an antigen, including a hapten, and an amino acid sequence to which a second antibody binds; wherein the first antibody is linked to the second antibody by a biotin-avidin-biotin link.
 12. A method for redirecting the specificity of an antibody, which comprises contacting said antibody with an antigen/antibody exchanger,wherein said antigen/antibody exchanger comprises (i) a first amino acid sequence comprising a first antigen which is recognized by said antibody, wherein said first amino acid sequence is linked to (ii) a second amino acid sequence which specifically binds to a second antigen, under conditions in which said antigen/antibody exchanger binds to said antibody to form a complex which is capable of binding to said second antigen, wherein the link is a covalent or a botin-avidin-biotin link.
 13. A method of claim 12 wherein said covalent linkage is a peptide bond.
 14. A method of claim 12, wherein said second amino acid sequence comprises a complementarity determining region (CDR) of an antibody.
 15. A method for redirecting the specificity of an antibody, which comprises contacting a first antigen with an antigen/antibody exchanger,wherein said antigen/antibody exchanger comprises (i) a first amino acid sequence comprising a second antigen which is recognized by said antibody, wherein said first amino acid sequence is linked to (ii) a second amino acid sequence which specifically binds to said first antigen, under conditions in which said antigen/antibody exchanger binds to said first antigen to form a complex which is capable of binding to said antibody, wherein the link is a covalent or a biotin-avidin-biotin link.
 16. A method of claim 15 wherein said covalent linkage is a peptide bond.
 17. A method of claim 15, wherein said second amino acid sequence comprises a complementarity determining region (CDR) of an antibody. 